Bobbin tester



March` 23, 1937.

C. D. GREENTREE BOBBIN, TESTER Filed June 29, 1955 x an vrlllll/lllllI/ ll/L u Jllllllllllllllllllllllllllllllllllllll 49 Hl Attowneg.

Parental Mar. 23, 1937 BOBBIN TESTER Charles D. Greentree, Schenectady, N. Y., assigner to General Electric Company, a corporation oi' New York Application June 29, 1935, serial No. 29,171

. 4 Claims.

My invention relates to balance-testing devices and concerns particularly apparatus for testing the balance of bobbins used in textile mills.

Most textile mills utilize many thousands of high-speed spindles. Wooden bobbins on which the thread is to be Wound are slipped over these spindles and then rotate with the spindles at speeds of approximately ten thousand revolutions per minute, thus winding the threadbn to the l0 bobbins. If these wooden bobbins are` out of balance, considerable vibration will be caused. This vibration, in turn, will cause the spindles to throw oil on the thread to be wound on to the bobbin and will sometimes cause breaking of the thread due to the jerky motion ofthe bobbin-winding action. Furthermore, an unbalanced bobbin Will cause the spindle to Wear out very quickly.

It is an object of my invention to obviate these difculties by providing a simple and easily operated device for quickly testing the balance of the bobbins before they are admitted. to the mili :door to be used on the spindles.

Other and further objects and advantages will become apparent as the description proceeds.

In carrying out my invention in its preferred form, a spindle and base `are set up in a semi-J flexible type of mounting'with a vibration-detecting device, such as a phonograph pick-up, at-v tached to the lower part of the base. An indieating lamp and a suitable amplifier connected between the vibration detector and the lamp circuit are provided to produce indications whenever a'bobbin being tested exhibits excessive unbalance.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. A better understanding of vmy invention may be obtained from the following description taken in connection withthe accompanying drawing in which Fig. 1 is a view in perspective of apparatus constructed in accordance with my invention; Fig. 2 is an elevation of the apparatus of Fig. 1 showing the enclosing casein cross section; Fig. 3 is a diagram of the electrical circuits of the apparatus; Fig. 4 is a view partially insection showing morein detail the arrangement of the spindle and base of Figs. 1 and 2, and Fig. 5 is an exploded detailed view of a portion of the vibration detector.

i Referring now more in detailv to the drawing in which like reference characters are used to designate like parts throughout, I have shown a. standard textile mill bobbin II mounted upon a textile mill spindle I2 of standard manufacture. Suchv spindles are customarily of the self-centering (Cl. 'I3-51) type mounted in `a bearing housing or base I3. 'Ihe spindle carriesa pulley I4 to permit rotation of the spindle` by a belt I5 driven by amotor I5' and is arranged to have the'bobbin II mounted on the upper end of the spindle. The lower portion of the spindle 2 is rotatably supported in thebase I3. The spindle I2 and the base I3 with all the details thereof are of thestandard construction used in large numbers in textile mills and need, therefore, not be4 further described.

' In my apparatus, however, a special mounting is provided'for the spindle and base. The arrangement is preferably such that the spindle and base are semifiexibly mounted in that theyv are free to oscillate about the mounting in one plane but not in a plane perpendicular thereto. This type of mounting may be accomplishedby 'means of a spring strip I6 having an annular portion Il in the middle thereof or, if desired, by a pair of spring strips I6 having semicircularportions at the middle thereof adapted to surround the base I3 near the upper end thereof. It will be' understood that the nut I3 and the washer ,I 9 are tightened against the edge of the portion I1 of the spring strip I B to insure the security of the mounting of the spindle and base. The ends of the spring strip I6 are preferably rigidly fastened in suitable slots in theframe or in the walls of an enclosing case 20.

A vibration detector of any suitable type, such as an electromagnetic phonograph pickup 2|, is attached to the lower end of the base Iii.` Such an electromagnetic' pick-up may be of the type Y and construction described more in f detail in United StatesPatent No. 1,906,615 to Kendall, assignedto the same assignee as the present application.v The pick-up 2| is adapted for attachment to a protruding needle and I provide aA clamping arrangement 22 having a needle portion 23 adapted for attachment to the pick-up 2|. The clamping arrangement. 22 may consist simply of a collar 2l Vadapted to surround the end of the base vI3 having the needle 23 attached thereto axially and having knurled headed screws 25 `to permit clamping the collar 24 to the base I3.

The type of pick-up 2| shown in the drawing consists of a permanent magnet 26 with pole pieces 21 and 28. Thepole pieces 21 and 28` have their polar projections divided into two parts, 29, 30 and 3|, 32, respectively. An armature 33 of Vmagnetizable material is `pivotally mounted in the air gap between the pole pieces and is transverse to the direction of the lines of flux crossing froml pole portion 30 to pole portion 32 and from pole portion 29 to pole portion 3|.

A coil 34 is so mounted as to surround the armature 33. 'The coil 34 is connected to an amplifying unit 35 which, in turn, is connected to an indicating lamp 36.

` The electrical circuit of the amplifier 35 is shown in Fig. 3. The amplifier 35 comprises a three-element electric discharge device 31 which maybe of the gas or vapor filled type, for example, including an anode 39, a cathode 48, and a control electrode 4 I. Power is supplied by an alteri hating-current source 38. A transformer 42 energized by the source of current may be provided for heating the cathode 48 and a full-wave rectifier 43 ofthe copper oxide type, for example, energized by the source 38 through a transformer44 may be provided for supplying a unidirectional biasing voltage tothe control electrode 4I. Preferably, a condenser 45 is connected across the output terminals of the rectifier 43 to stabilize the control electrode circuit and i to determine whether the bobbins tested should be rejected or accepted without any qualitative determination as to the degree of unbalance, the apparatus is so adjusted before making-'tests on a lot of bobbins that the lamp 36 lights up whenever an undesirably unbalanced bobbin is placed upon the spindle I2 but remains dark when the vbobbin tested is perfectly balanced or its degree of unbalance is withinpermissible limits. This adjustment is most conveniently made by placing upon the spindle I2 a bobbin which has been found in actual service to be satisfactory. The potentiometer 46 is then adjusted by means of the knob 48 to the pointl at which the lamp 36 is just caused to go out. Thereafter, when a defective bobbin is placed upon the spindle I2, the spindle will be set in vibration, causing the vibration detector 2| to light the lamp 36.

In response to the vibration, the armature 33 of the pick-up 2l oscillates about its pivotal axis between the pole pieces 21 and 28. It will be seen that, when the armature 33 is deflected toward the pole portions 32 and 28, the minimum reluctance of the magnetic circuit will be through these pole portions and, when the armature 33 is deflected .toward the pole portions 38 and 3l, the minimum reluctance will be through the latter pole portions. Consequently, the direction ofthe flux lengthwise through the armature 33 will reverse at the frequency of oscillation ,of the spindle I2 and the variation in reluctance willl depend upon the amplitude of vibration caused by unbalance of the bobbin I I. Relative motion between the armature'33 and the pole pieces 21 and 28 occurs when the base I3 vibrates becausel the inertia due to the mass of the pick-up 2| tends to hold it stationary in space and theflexibility of the armature pivot permits such action. On the other hand, the armature 33 is rigidly attached to the base I3 and must partake of its vibration.

The variations in reluctance of the magnetic circuit will cause variations in fiux threading the coil 34 and, consequently, alternating voltages will be induced in the winding 34 whichare amplified will be made conducting and a current will flow through the indicating lamp 36. It is thus apparent thatgby adjustment of the potentiometer 46, the apparatus may be adjusted to. segregate bobbins having any degree of unbalance according to the desires of the mill operator or the requirements of the machinery of the mill.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means. f

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A balance-testing device for rotating objects comprising in combination, a rotatable vertical spindle for carrying an object to be tested in rotation, a base carrying said spindle, flexible mounting means supporting said base near its upper end, said base being wholly supported thereby, means for rotating said spindle, an electro-magnetic pick-up mounted upon the lower end of said base, and current-responsive means electrically connected to said pick-up.

2. A balance-testing device for rotating objects comprising in combination, a rotatable spindle for carrying an object to be tested in rotation, means for flexibly supporting said spindle solely at a point intermediate its ends, means for rotating said spindle, said spindle being adapted to have the tested object mounted on the portion thereof toward one end, and a vibration-responsive device mounted at the other end of said spindle.

3. A balance-testing device for rotating objects comprising in combination, a rotatable spindle for carrying an object to be tested in rotation, a bearing housing in which one end of said spindle is supported, the other end being adapted for mounting the object to be tested, a spring strip with its`\ ends rigidly supported and attached at the middle to said bearing housing to provide a flexible Support therefor, a vibration detector mounted on said bearing housing at a point spaced from the point of attachment of said spring strip, and means for rotating said spindle.

4. A balance tester for textile mill bobbins comprising in combination, a textile mill spindle and base, means for rotating the spindle, a spring strip mounting for said base, and a vibration detector mounted upon the lower end of said base,

said base being wholly supported by said mount- 

